## Boxxbike Valkyrie : 12kw crank concentric mid drive with left hand motor drive

General Discussion about electric bicycles.
scrambler   1 kW

Posts: 479
Joined: Aug 10 2015 7:23pm
Location: San Francisco Bay Area (USA)

### Re: Boxxbike Valkyrie: Torque sensing ideas

Actually, the best way to eliminate any influence of the rear sprocket size would be to add a fixed wheel on the frame as in the schematic below. The wheel would be attached at the back of the swing arm, so basically invisible.

Now, In order to see if we could predict the feasibility before actually getting a sensor and trying it, I made the schematic below to calculate the pressure on the wheel attached to the sensor, based on the pedal pressure, the bike dimensions and the deviation angle created by the sensor positioning.
Note: There is as small approximation done carrying the opposite chain tension forces in a single point, but the error induced should be negligible.

Assuming my rusted physics are correct ), If I can find the value of the force applied to the sensor axle location that corresponds to the sensor output range, we can predict if that configuration can work with that sensor as is.

ID Bike (Sensors (idbike.com) ) mentions a usable TMM4 sensor range of 40Nm in high sensitivity mode and 100Nm in medium sensitivity mode, but without knowing how they measure that, it does not give us the axial force that correspond to these torques at the sensor level.
I have sent an inquiry to ID Bike and Tranzx, we will see if they respond...
Last edited by scrambler on Feb 20 2022 12:56pm, edited 1 time in total.

scrambler   1 kW

Posts: 479
Joined: Aug 10 2015 7:23pm
Location: San Francisco Bay Area (USA)

### Re: Boxxbike Valkyrie : Torque sensing ideas

Here is a simpler design that would also pull on the torque sensor more symmetrically.

The sensor would be mounted at the back of the swing arm, so mostly concealed.
The chain wheel would hang from it and could be adjusted vertically to adjust the chain deviation angle, which in turns changes the range of pulling force on the sensor.

Comments welcome
Last edited by scrambler on Feb 20 2022 12:56pm, edited 2 times in total.

scrambler   1 kW

Posts: 479
Joined: Aug 10 2015 7:23pm
Location: San Francisco Bay Area (USA)

### Re: Boxxbike Valkyrie :

@sn0wchyld do you have an update for us

Aside for any new feedback you may have using the bike, I was wondering about the following.
1. From your last remarks on cutoff brakes,
sn0wchyld wrote:
Mar 13 2021 9:38am
For the cutout issue I'm going to chat to the guys about adding it in for the pedal modes, I have some MT5E's so getting a reliable switch is taken care of. I also kind of want a 2 stage switch so very hard pulls on the breaks do cutout the motor in all modes... not essential but a good 'oh shit' option if it can be added.
I assume there is no emergency cutoff switch on the bike, and if so did you get around installing your MT5e levers?
If you did, are these closers (normally open) or openers (normally closed), and did you get info from Boxxbike on how to connect them to the controller?

2. On that subject, is there any safety system like a key that prevents anyone from starting the bike?

3. Have you had any further discussion with Boxxbike on the items below?
• Variable regen throttle
• Enabling the throttle in Pedal assist mode

On my side, I have ordered a TMM4 sensor so I can test if it could be used to measure pedal power using the chain tension.

Thanks
Last edited by scrambler on Feb 20 2022 12:56pm, edited 1 time in total.

sn0wchyld   1 MW

Posts: 1862
Joined: Mar 18 2011 8:27pm
Location: South Aus.

### Re: Boxxbike Valkyrie : 12kw crank concentric mid drive with left hand motor drive

scrambler wrote:
Apr 05 2021 2:20pm
@sn0wchyld do you have an update for us

Aside for any new feedback you may have using the bike, I was wondering about the following.
1. From your last remarks on cutoff brakes,
sn0wchyld wrote:
Mar 13 2021 9:38am
For the cutout issue I'm going to chat to the guys about adding it in for the pedal modes, I have some MT5E's so getting a reliable switch is taken care of. I also kind of want a 2 stage switch so very hard pulls on the breaks do cutout the motor in all modes... not essential but a good 'oh shit' option if it can be added.
I assume there is no emergency cutoff switch on the bike, and if so did you get around installing your MT5e levers?
If you did, are these closers (normally open) or openers (normally closed), and did you get info from Boxxbike on how to connect them to the controller?

2. On that subject, is there any safety system like a key that prevents anyone from starting the bike?

3. Have you had any further discussion with Boxxbike on the items below?
• Variable regen throttle
• Enabling the throttle in Pedal assist mode

On my side, I have ordered a TMM4 sensor so I can test if it could be used to measure pedal power using the chain tension.

Thanks
hey mate

no sorry, haven't done any of it, just been enjoying the bike. 'finally' managed to break something on it too!! just the seat, so nothing to loose sleep over. Shame as it was quite comfortable. Only other issue ive experienced is the controller can occasionally loose sync with the motor when taking off, and you get the characteristic shudder. Apparently a known issue with the current firmware, but is rare enough to not be an issue (maybe 1 event or less every 2 rides?). Resolves itself after letting off throttle. Rest of the bike has been issue free.

there's no safety system, which I think ill add at some point particularly for when you drop the bike and the throttle can get twisted. Easiest way is just a simple throttle wire cut via a pull switch/plug... but will talk to the boxxbike guys too.

nothing on variable regen/throttle. For me ive been riding in throttle mode 90% of the time, the lowest power mode has no regen and the bike has very low drag from the motor (guessing salient pole motor). Quite comfortable on the flats to around 20-25km'h.

Still very impressed. Finally got the ebike grin I've been looking for for years... The issues ive reported are pretty minor and otherwise its been a blast. The motor is very impressive, ~30min of burning up hills, trying to wheelie (i suck btw), and generally pushing the bike as hard as i can ride (9kw mode) and the casing is 'warm' - maybe 35C at most on a 15C day. They tell me they had a pro MX rider race it round a track on 14kw with no thermal issues and im inclined to believe them... maybe in a aussie summer it'll have some issues but outside of those 45C days i think it'll be fine, and quite possibly better than the surron motor, particularly pound for pound.

The niggles I reported earlier ive pretty much gotten used to. Q factor is still a little wide, and can make some narrow gaps more difficult, so will be getting some 0 offset pedals, but the 'tallness' etc im used to now, and the clearance over obstacles is great - right over stuff I know I'd be scraping the surron on.

Only pressing thing for me to solve now is the front end feels a bit harsh. The suntor shocks transfer a lot of the vibration from high speed small bumps, so will be playing with the setup to see if i can get it sorted. Does make me wonder if I should have gone the whole hog and gotten the ohins, even just for the front. DNM rear is doing surprisingly well so far, though have a spare fox DHX2 so will swap that at some point.

scrambler   1 kW

Posts: 479
Joined: Aug 10 2015 7:23pm
Location: San Francisco Bay Area (USA)

### Re: Boxxbike Valkyrie

Thanks for the update, all looking good

Whenever you do speak with Boxxbike to get some changes / upgrades that require access to Silixcon, let me know how that goes.

I am curious to know if they are open to cooperation on controller programming for customization or not.

Take care and visit us here once in a while
Last edited by scrambler on Feb 20 2022 12:56pm, edited 2 times in total.

briangv99   1 kW

Posts: 329
Joined: Jan 15 2008 4:14am
Location: Canberra, Australia

### Re: Boxxbike Valkyrie : 12kw crank concentric mid drive with left hand motor drive

sn0wchyld wrote:
Mar 13 2021 9:38am
if anyone knows of some 'striaght' square tapers please let me know.
I've bought directly from Miranda a couple times, their cranks are beautifully made and available in straight qf:0

https://www.mirandabikeparts.com/en/shop/e-bike/delta/

scrambler   1 kW

Posts: 479
Joined: Aug 10 2015 7:23pm
Location: San Francisco Bay Area (USA)

### Re: Boxxbike Valkyrie :

@sn0wchyld, I hope you are still enjoying the bike, and I have some quick questions for you.

1- Can you confirm if the regen also acts as a motor cutoff?
What I mean is that is you have the throttle twisted to move forward and you press the brake with the regen sensor, does that cuts off power and activates regen?

2- Also, from what you can see, does it look like the regen sensor could easily be moved onto the front brake instead of the rear?
I figured the most used brake on a bike is the front brake, so it may be would be better to have the engine brake activated in the most frequent braking situations.

2- Last, have you had any discussion with Boxxbike about allowing the throttle to work on Pedal Assist mode?
It could either be an option for that mode, or exist as a third mode (PAS only, Throttle only, PAS & Throttle).

Thanks to let us know.
Cheers
Last edited by scrambler on Feb 20 2022 12:56pm, edited 1 time in total.

sn0wchyld   1 MW

Posts: 1862
Joined: Mar 18 2011 8:27pm
Location: South Aus.

### Re: Boxxbike Valkyrie : 12kw crank concentric mid drive with left hand motor drive

scrambler wrote:
Jun 01 2021 3:31pm
@sn0wchyld, I hope you are still enjoying the bike, and I have some quick questions for you.

1- Can you confirm if the regen also acts as a motor cutoff?
What I mean is that is you have the throttle twisted to move forward and you press the brake with the regen sensor, does that cuts off power and activates regen?

2- Also, from what you can see, does it look like the regen sensor could easily be moved onto the front brake instead of the rear?
I figured the most used brake on a bike is the front brake, so it may be would be better to have the engine brake activated in the most frequent braking situations.

2- Last, have you had any discussion with Boxxbike about allowing the throttle to work on Pedal Assist mode?
It could either be an option for that mode, or exist as a third mode (PAS only, Throttle only, PAS & Throttle).

Thanks to let us know.
Cheers
Hey mate
1. no more switch for regen - apparently was unreliable so its now a drag brake. So no cutoff - from having one on the surron i think i prefer that anyway - its dangerous when you can touch the brakes and have the throttle in any position (without the audio feeback you'd get from a ICE) and when you release the brake its like dropping the clutch... I'm going to wire a pull cord to cutout the throttle easily (rather than turning off the bike) but otherwise I prefer it this way.
2. see 1.
3. haven't asked - im slowly making progress on a torque sensor that ill use with the normal throttle modes (ie convert torque to a throttle signal with an arduino) - shouldn't be too hard to use 2 analog inputs and an analog output to combine both modes.

scrambler   1 kW

Posts: 479
Joined: Aug 10 2015 7:23pm
Location: San Francisco Bay Area (USA)

### Re: Boxxbike Valkyrie :

sn0wchyld wrote:
Jun 03 2021 12:39am
scrambler wrote:
Jun 01 2021 3:31pm
@sn0wchyld, I hope you are still enjoying the bike, and I have some quick questions for you.

1- Can you confirm if the regen also acts as a motor cutoff?
What I mean is that is you have the throttle twisted to move forward and you press the brake with the regen sensor, does that cuts off power and activates regen?

2- Also, from what you can see, does it look like the regen sensor could easily be moved onto the front brake instead of the rear?
I figured the most used brake on a bike is the front brake, so it may be would be better to have the engine brake activated in the most frequent braking situations.

2- Last, have you had any discussion with Boxxbike about allowing the throttle to work on Pedal Assist mode?
It could either be an option for that mode, or exist as a third mode (PAS only, Throttle only, PAS & Throttle).

Thanks to let us know.
Cheers
Hey mate
1. no more switch for regen - apparently was unreliable so its now a drag brake. So no cutoff - from having one on the surron i think i prefer that anyway - its dangerous when you can touch the brakes and have the throttle in any position (without the audio feeback you'd get from a ICE) and when you release the brake its like dropping the clutch... I'm going to wire a pull cord to cutout the throttle easily (rather than turning off the bike) but otherwise I prefer it this way.
2. see 1.
3. haven't asked - im slowly making progress on a torque sensor that ill use with the normal throttle modes (ie convert torque to a throttle signal with an arduino) - shouldn't be too hard to use 2 analog inputs and an analog output to combine both modes.
Sorry for late answer, I did not get notification from ES....

What do you mean by a drag brake, can you elaborate?

What type of torque sensor system are you trying to use, can you share?
I am about to pull the trigger on the Boxxbike, so more interested than ever

Also, why bother with Arduino, when the Silixcon can do it?
All you need is get programming approval from Boxxbike to Silixcon, and they should be able to help with the programming.
Last edited by scrambler on Feb 20 2022 12:57pm, edited 1 time in total.

sn0wchyld   1 MW

Posts: 1862
Joined: Mar 18 2011 8:27pm
Location: South Aus.

### Re: Boxxbike Valkyrie : 12kw crank concentric mid drive with left hand motor drive

scrambler wrote:
Jun 07 2021 4:23pm
sn0wchyld wrote:
Jun 03 2021 12:39am
scrambler wrote:
Jun 01 2021 3:31pm
@sn0wchyld, I hope you are still enjoying the bike, and I have some quick questions for you.

1- Can you confirm if the regen also acts as a motor cutoff?
What I mean is that is you have the throttle twisted to move forward and you press the brake with the regen sensor, does that cuts off power and activates regen?

2- Also, from what you can see, does it look like the regen sensor could easily be moved onto the front brake instead of the rear?
I figured the most used brake on a bike is the front brake, so it may be would be better to have the engine brake activated in the most frequent braking situations.

2- Last, have you had any discussion with Boxxbike about allowing the throttle to work on Pedal Assist mode?
It could either be an option for that mode, or exist as a third mode (PAS only, Throttle only, PAS & Throttle).

Thanks to let us know.
Cheers
Hey mate
1. no more switch for regen - apparently was unreliable so its now a drag brake. So no cutoff - from having one on the surron i think i prefer that anyway - its dangerous when you can touch the brakes and have the throttle in any position (without the audio feeback you'd get from a ICE) and when you release the brake its like dropping the clutch... I'm going to wire a pull cord to cutout the throttle easily (rather than turning off the bike) but otherwise I prefer it this way.
2. see 1.
3. haven't asked - im slowly making progress on a torque sensor that ill use with the normal throttle modes (ie convert torque to a throttle signal with an arduino) - shouldn't be too hard to use 2 analog inputs and an analog output to combine both modes.
Sorry for late answer, I did not get notification from ES....

What do you mean by a drag brake, can you elaborate?

What type of torque sensor system are you trying to use, can you share?
I am about to pull the trigger on the Boxxbike, so more interested than ever

Also, why bother with Arduino, when the Silixcon can do it?
All you need is get programming approval from Boxxbike to Silixcon, and they should be able to help with the programming.
I want to try and do it without modifying the bike, and i dont know if all what I want to program is available. I know with arduino I can get modules setup such that I can adjust stuff on the fly, not sure thats possible with silix. Then I have to get programming access in the first place

drag brake - when there's no throttle input there's gentle regen braking - enough to hold your speed on a mild slope, helps with braking but not near as powerful as it could be. 'always on' too, so no switch.

Torque system is using a strain guage to measure chain tension, and using this as a throttle input signal. will show somethign when I have something worth showing... to busy with work atm to even ride much, much less build stuff.

scrambler   1 kW

Posts: 479
Joined: Aug 10 2015 7:23pm
Location: San Francisco Bay Area (USA)

### Re: Boxxbike Valkyrie : Torque sensing ideas

I am definitely interested in seeing what type of strain gauge you are testing, you can send a PM if you prefer

For regen, if it is activated by the throttle cutoff, That is good as it basically behaves like an engine brake.
The only limitation I suppose is that there must be no regen available when in Pedal assist mode.
Last edited by scrambler on Feb 20 2022 12:57pm, edited 1 time in total.

scrambler   1 kW

Posts: 479
Joined: Aug 10 2015 7:23pm
Location: San Francisco Bay Area (USA)

### Re: Boxxbike Valkyrie :Torque sensing ideas

I had initially dismissed load cells as a sensor because of their size and weight, but came across the one below going up to 50kG or even 100kg.
Very small and light form factor, and the 50kg one should probably be suitable.
https://www.ebay.com/itm/333788724543

Combined with a small Analog amplifier board like below
https://www.amazon.com/dp/B08QM9SM1W?ps ... ct_details

It should be able output a zero to 5VDC signal, which is what the Silixcon controller can take as Torque sensor input, or be simply combined with the throttle signal (which I think is also 0-5VDC) with minimum electronics.

Or with an analog to digital board like below
https://www.amazon.com/HiLetgo-Weighing ... ljaz10cnVl

It could interface with the arduino...

What I don't' know is if these load cells have any lag...
I am ordering one to test
Last edited by scrambler on Feb 20 2022 12:57pm, edited 1 time in total.

scrambler   1 kW

Posts: 479
Joined: Aug 10 2015 7:23pm
Location: San Francisco Bay Area (USA)

### Re: Boxxbike Valkyrie : Purchase report

Well I am now the proud owner of a Boxxbike Valkyrie

Things I noticed compared to what was discussed previously:
• Cranks are straight, so the Q factor is 261mm, and comfortable.
• There is a USB port at the bottom of the display which is good news as I could Velcro a phone mount at the top of the battery box for rides that need a GPS.
• Cadence sensor on streets is doing a pretty decent job, it not only has a smooth power ramp up, but it seems to be adaptive to the speed of pedaling which improves the feel. Still not as nice a torque sensing, and I will need to see how that translate on trails, but better than expected.

Things Boxxbike was kind enough to accommodate:
• After hearing the bike now came in Glossy black, I asked them if they could do a Mat / Satin clear coat on mine and they agreed. The result is perfect and exactly what I expected, and looks more like the Bike in the site FAQ videos.
• Normally Boxxbike applies the stickers before the clear coat which helps protect them, but I wanted to do my own decal design so they agreed not to apply the stickers. I now have the bike with the design I like, which I think makes the bike frame look thinner.
• I wanted the possibility to power some lights, so Boxxbike was kind enough to add a 48V connector on the side of the headset.

Things I am adding or thinking of changing:
• Dropper post:
Because 96cm is the max seat height at rest that I like, and given this is the lowest seat position on that bike, I did not order a dropper post. What I did not realize is that the Bottom bracket is quite high (390 mm, good for trails), and so I could use another 100mm when pedaling.
So I ordered myself a Bike Yoke Revive 125mm dropper post, its insertion area is 230mm which is just the right size for the bike. I will be able to have the post inserted all the way as to retain my low minimum saddle height but get the extra 100mm or so I could use when pedaling.
(The bike seat tube from top of clamp to bottom is 223mm, and you can extend an extra 10mm below that keeping enough clearance for the shock.)

• Kickstand:
I know most will scream bloody murder, but I am going to use that bike for a lot of different things, so I want the convenience… There is a tensioner protective cover on the rear that is mounted on a welded plate. It looks like I should be able to use it to attach a 2 bolt kickstand like this one
https://www.amazon.com/Portland-Design- ... ods&sr=1-1
Will report back

• IGH:
I plan to replace the derailleur with the recently release Kindernay VII Internal Geared Hub.
That new Kindernay will be perfect for a bike like this. Less more appropriate number of gears, but still with a 430% range and higher top gear ratio.
It will double the max pedaling speed while retaining enough low gears for trails. It also has a new Single side shifter which is good is you have a dropper post trigger on the left.
I am waiting for the final details on the new Torque arm they use on the Hub so I can validate the Motor sprocket adapter I had already designed. I will post back with more details when I get to it (first shipment are not before another month or so….)
The 9 speed derailleur has a range of 290% (11 to 32). With it, a cadence of 80rpm produces a speed range of 7mph to 20mph.
The Kindernay VII 430% range and max ratio of 2.07 combined with a 14T / 34T sprocket set, would give 8mph to 35mph at 80rpm. A 12T / 34T would make that 9mph to 40mph.

• Torque sensor:
I bought a small load cell as mentioned in my previous thread, and combined with the small electronic board, I can get a 0-5VDC signal out of it that I can adjust to match any force input range. So at one point I will look into testing that as a throttle replacement, and if it works at combining it with the throttle.

I have not done any serious riding yet, but so far the Bike looks and feel amazing !

To be followed
Other articles
Purchase report:
viewtopic.php?f=3&t=94174&start=75#p1675901

Customizations:
viewtopic.php?f=3&t=94174&start=100#p1676907

Torque sensing pedal assist:
viewtopic.php?f=3&t=94174&start=100#p1679413
viewtopic.php?f=3&t=94174&start=100#p1686510

Regenerative braking:
viewtopic.php?f=3&t=94174&start=100#p1690743

Kindernay IGH conversion:
viewtopic.php?f=3&t=94174&start=100#p1709402
Last edited by scrambler on Apr 10 2022 12:15pm, edited 3 times in total.

SlowCo   10 MW

Posts: 2111
Joined: Jan 05 2015 5:43pm
Location: The Netherlands

### Re: Boxxbike Valkyrie : 12kw crank concentric mid drive with left hand motor drive

scrambler wrote:
Sep 11 2021 4:25pm
Well I am now the proud owner of a Boxxbike Valkyrie

I have not done any serious riding yet, but so far the Bike looks and feel amazing !
Congratulations!
Where are the photos?

scrambler   1 kW

Posts: 479
Joined: Aug 10 2015 7:23pm
Location: San Francisco Bay Area (USA)

### Re: Boxxbike Valkyrie : Purchase report

I will get to it
Last edited by scrambler on Feb 20 2022 12:58pm, edited 1 time in total.

scrambler   1 kW

Posts: 479
Joined: Aug 10 2015 7:23pm
Location: San Francisco Bay Area (USA)

### Re: Boxxbike Valkyrie : Purchase report

Here you go

I am going to get a better front fender though
Last edited by scrambler on Feb 20 2022 12:58pm, edited 1 time in total.

john61ct   100 GW

Posts: 8441
Joined: Dec 18 2018 2:06pm

### Re: Boxxbike Valkyrie : 12kw crank concentric mid drive with left hand motor drive

So what's it weigh?

Any way to verify max torque on what you received?

Would the IGH withstand it OK if you hit that number?

Wonder if a frame swap (or mod) could turn this into a HD cargo platform?

8kW sure is a nice jump from the usual DIY options.

Is their controller re-programmable? I don't need speed, but do want to push 500+lbs up steep long hills.

Look forward to off-road reports, big part of my use case.

scrambler   1 kW

Posts: 479
Joined: Aug 10 2015 7:23pm
Location: San Francisco Bay Area (USA)

### Re: Boxxbike Valkyrie : Purchase report

john61ct wrote:
Sep 11 2021 10:43pm
So what's it weigh?
Any way to verify max torque on what you received?
Weight is supposed to be 37kg. I did a quick scale and got 40kg, will need to double check.
No way to check the torque
john61ct wrote:
Sep 11 2021 10:43pm
Would the IGH withstand it OK if you hit that number?
The beauty of this bike is the Dual power train, the IGH will never see any of the motor power, just the pedaling effort, so zero issue there
john61ct wrote:
Sep 11 2021 10:43pm
Is their controller re-programmable? I don't need speed, but do want to push 500+lbs up steep long hills.
The controller is the Silixcon, so fully programmable, but you would probably have to negotiate with Boxxbike to unlock it, or give up your warranty.
Last edited by scrambler on Feb 20 2022 12:58pm, edited 1 time in total.

john61ct   100 GW

Posts: 8441
Joined: Dec 18 2018 2:06pm

### Re: Boxxbike Valkyrie : 12kw crank concentric mid drive with left hand motor drive

john61ct   100 GW

Posts: 8441
Joined: Dec 18 2018 2:06pm

### Re: Boxxbike Valkyrie : 12kw crank concentric mid drive with left hand motor drive

scrambler wrote:The beauty of this bike is the Dual power train, the IGH will never see any of the motor power, just the pedaling effort, so zero issue there
Interesting.

But wouldn't lugging at high load / steep slope / low speed be reduced by using the IGH?

Wonder how yours compares to the Rohloff, withstanding n.M in that scenario, standing start mid-mountain facing up hill?

scrambler   1 kW

Posts: 479
Joined: Aug 10 2015 7:23pm
Location: San Francisco Bay Area (USA)

### Re: Boxxbike Valkyrie :

john61ct wrote:
Sep 11 2021 11:09pm
This one? https://imgur.com/hxslj25

thread viewtopic.php?t=98246
Yes https://silixcon.com/
I believe it is the SC, but not 100% sure
Last edited by scrambler on Feb 20 2022 12:59pm, edited 1 time in total.

scrambler   1 kW

Posts: 479
Joined: Aug 10 2015 7:23pm
Location: San Francisco Bay Area (USA)

### Re: Boxxbike Valkyrie :

john61ct wrote:
Sep 11 2021 11:13pm
scrambler wrote:The beauty of this bike is the Dual power train, the IGH will never see any of the motor power, just the pedaling effort, so zero issue there
Interesting.
But wouldn't lugging at high load / steep slope / low speed be reduced by using the IGH?
Wonder how yours compares to the Rohloff, withstanding n.M in that scenario, standing start mid-mountain facing up hill?
The Kindernay XIV is the equivalent of the Rohloff (same range and number of gears), but Kindernay is a true thru Axle system, has an Hydraulic shifter, and uses a cage system to make swaping wheel easier.
https://kindernay.com/products/

But on an E-bike, 14 gears is overkill, so they just released a 7 gears version with a little less range that will be perfect for the Job.

As I mentioned, because the Motor Power train is separate from the pedaling powertrain, none of the motor power goes through the IGH. The motor delivers its power without any gears directly to the left side sprocket.
The IGH is only used to provide gears for the pedaling side

So you can gun the throttle and unleash 10kW going uphill without putting any effort on gears.
Same goes if you are using Pedal assist the cadence sensor replaces the throttle, but ultimately when the controller activates the motor, that power goes directly to the rear wheel without gears
Last edited by scrambler on Feb 20 2022 4:47pm, edited 1 time in total.

sn0wchyld   1 MW

Posts: 1862
Joined: Mar 18 2011 8:27pm
Location: South Aus.

### Re: Boxxbike Valkyrie : 12kw crank concentric mid drive with left hand motor drive

haha nice mate, and im jealous there's a few options you mention there that i should have asked for on mine, like mat paint, no stickers, 48v outpout etc

mines still going great, though i have managed to overheat it once (only to the point of thermal rollback, still worked but lost some of the oomph of torque) - was a hot day and I had been riding like a maniac for a good hour or so on steep, tight tracks, so still not unhappy. might have to improve the cooling some when i eventually get back to aus though, probably just a couple of small heatsinks will do.

only issue ive come across now is the rear 2.8 tyre and rim is not up to the abuse ive been putting the bike through... few pinch flats (even with tannus liners) and the rim is pretty dinged up despite running 40psi. considering trying to find a lightweight 21'' mx wheel for the rear, but hard to find people to build them here in france... they dont really like 'outside the box' much... but need to find a solution, had a couple of 5-8km walks as a result, really takes the edge off the fun.

glad you;ve finally bitten the bullet

ive finally gotten round to doing the arduino code for the torque sensor (using a chain pulley) - havent done the mechanics yet though... broke my hand the other week so had some spare time
scrambler wrote:
Sep 11 2021 4:25pm
Well I am now the proud owner of a Boxxbike Valkyrie

Things I noticed compared to what was discussed previously:
• Cranks are straight, so the Q factor is 261mm, and comfortable.
• There is a USB port at the bottom of the display which is good news as I could Velcro a phone mount at the top of the battery box for rides that need a GPS.
• Cadence sensor on streets is doing a pretty decent job, it not only has a smooth power ramp up, but it seems to be adaptive to the speed of pedaling which improves the feel. Still not as nice a torque sensing, and I will need to see how that translate on trails, but better than expected.

Things Boxxbike was kind enough to accommodate:
• After hearing the bike now came in Glossy black, I asked them if they could do a Mat / Satin clear coat on mine and they agreed. The result is perfect and exactly what I expected, and looks more like the Bike in the site FAQ videos.
• Normally Boxxbike applies the stickers before the clear coat which helps protect them, but I wanted to do my own decal design so they agreed not to apply the stickers. I now have the bike with the design I like, which I think makes the bike frame look thinner.
• I wanted the possibility to power some lights, so Boxxbike was kind enough to add a 48V connector on the side of the headset.

Things I am adding or thinking of changing:
• Dropper post:
Because 96mm is the max seat height at rest that I like, and given this is the lowest seat position on that bike, I did not order a dropper post. What I did not realize is that the Bottom bracket is quite high (390 mm, good for trails), and so I could use another 100mm when pedaling.
So I ordered myself a Bike Yoke Revive 125mm dropper post, its insertion area is 230mm which is just the right size for the bike. I will be able to have the post inserted all the way as to retain my low minimum saddle height but get the extra 100mm or so I could use when pedaling.
(The bike seat tube from top of clamp to bottom is 223mm, and you can extend an extra 10mm below that keeping enough clearance for the shock.)

• Kickstand:
I know most will scream bloody murder, but I am going to use that bike for a lot of different things, so I want the convenience… There is a tensioner protective cover on the rear that is mounted on a welded plate. It looks like I should be able to use it to attach a 2 bolt kickstand like this one
https://www.amazon.com/Portland-Design- ... ods&sr=1-1
Will report back

• IGH:
I plan to replace the derailleur with the recently release Kindernay VII Internal Geared Hub.
That new Kindernay will be perfect for a bike like this. Less more appropriate number of gears, but still with a 430% range and higher top gear ratio.
It will double the max pedaling speed while retaining enough low gears for trails. It also has a new Single side shifter which is good is you have a dropper post trigger on the left.
I am waiting for the final details on the new Torque arm they use on the Hub so I can validate the Motor sprocket adapter I had already designed. I will post back with more details when I get to it (first shipment are not before another month or so….)
The 9 speed derailleur has a range of 290% (11 to 32). With it, a cadence of 80rpm produces a speed range of 7mph to 20mph.
The Kindernay VII 430% range and max ratio of 2.07 combined with a 14T / 34T sprocket set, would give 8mph to 35mph at 80rpm. A 12T / 34T would make that 9mph to 40mph.

• Torque sensor:
I bought a small load cell as mentioned in my previous thread, and combined with the small electronic board, I can get a 0-5VDC signal out of it that I can adjust to match any force input range. So at one point I will look into testing that as a throttle replacement, and if it works at combining it with the throttle.

I have not done any serious riding yet, but so far the Bike looks and feel amazing !

To be followed

scrambler   1 kW

Posts: 479
Joined: Aug 10 2015 7:23pm
Location: San Francisco Bay Area (USA)

### Re: Boxxbike Valkyrie :

Glad to hear you are moving forward with the torque sensor, have you already checked what is the signal output of the Domino throttle, measured at the Headset connector?

I understand the Controller works with a 0-5VDC as throttle input, but the Domino is normally 12V nominal, So I am not sure how they have it configured at the headset Connector level.

Also, If you are still hoping to get the saddle back, I found two parts that could probably be adapted to do the job, or inspire a custom one.
The one below is for single bolt so would need to be adapted
https://www.sjscycles.co.uk/saddles/vk- ... r/?geoc=US

The one below is for dual bolt and I think could be used by cutting off the top part, keeping just the Bottom Ubar to attach to the Post, and use the Clamp from the top part to mount the saddle back on the U.
https://www.wish.com/product/5f1e7066e8 ... &share=web

But I understand what you meant, I tried riding with the saddle at the lowest position, and it is way too forward to be comfortable. I will see when I have the dropper post if that makes it better as the saddle will move back as it moves up, but may need to consider the system above too
Last edited by scrambler on Feb 20 2022 12:59pm, edited 2 times in total.

SlowCo   10 MW

Posts: 2111
Joined: Jan 05 2015 5:43pm
Location: The Netherlands

### Re: Boxxbike Valkyrie : 12kw crank concentric mid drive with left hand motor drive

SlowCo wrote:
Sep 11 2021 7:14pm
Congratulations!
Where are the photos?
scrambler wrote:
Sep 11 2021 8:12pm
Here you go
Wow
Very nice bike and great color and decals. Enjoy!